1. Field of the Invention
The present invention relates to a zoom lens system, an optical apparatus and a method for zooming the zoom lens system suitable for a still camera and a digital camera.
2. Related Background Art
Recently, an imaging optical apparatus such as a digital still camera, and a digital video camera using a solid-state imaging device has increasingly become high-performance and compact. In such an imaging optical apparatus, a zoom lens is generally used as an image-taking lens, so that it becomes possible for a photographer to easily take a picture with an ideal angle of view most suitable for the scene.
Among such zoom lenses, most of those installed in compact imaging optical apparatuses have a zoom ratio of about three, and most of them have a negative-leading type zoom lens in which a negative lens group is disposed to the most object side and at least one positive lens group is disposed to the image side thereof (for example, Japanese Patent Application Laid-Open No. 2006-208890).
However, a negative-leading type zoom lens tends to have a longer total lens length with respect to a focal length thereof. The tendency becomes conspicuous as making the angle of view in the wide-angle end state wider, or making the zoom ratio of the zoom lens larger. When such a zoom lens is forcibly made to be compact, refractive power of each lens group becomes too strong, so that it becomes difficult to correct aberrations. For example, the zoom lens disclosed in Japanese Patent Application Laid-Open No. 2006-208890 can be widened the angle of view. However, the zoom lens itself becomes extremely large with unrealistic dimension.